Medium-Voltage Switchgear with Vacuum Arc Interruption and Dry-Air Insulation
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Solution Overview
Problem
Existing load-break switches for medium voltage electric systems face challenges in achieving high-level dielectric insulation and arc-quenching capabilities while minimizing environmental impact, often compromising on structural compactness, reliability, and manufacturing costs.
Innovation Solution
A switching apparatus with electric poles featuring a vacuum interrupter and a motion transmission mechanism using lever and spring members to synchronize the movement of movable contacts, ensuring efficient arc-quenching and dielectric insulation, while using environment-friendly gases like dry air or gas mixtures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If SF6 gas is used for insulation and arc-quenching, then dielectric insulation and arc-quenching capabilities are improved, but environmental harm increases due to greenhouse gas emissions
Solution Approach 1:
The patent changes the physical state and composition parameters by using a vacuum environment instead of SF6 gas, and uses environmentally friendly alternative gases (like air or nitrogen) at different pressure conditions. This maintains the insulating and arc-quenching functions while eliminating the harmful environmental effects of SF6.
Solution Approach 2:
The patent employs a vacuum chamber creating an inert vacuum environment for the arc-quenching contacts, and alternatively uses inert or less harmful gases like nitrogen or air. This provides the necessary dielectric insulation and arc-quenching performance without the environmental damage caused by SF6 gas.
2Reliability
If multiple contact arrangements (air atmosphere for current carrying and vacuum for arc-quenching) are used, then arc-quenching capabilities and environmental friendliness are improved, but device complexity increases
Solution Approach 1:
The patent merges the current-carrying contacts and arc-quenching contacts into a single integrated contact arrangement within the vacuum chamber. The same contacts perform both functions of carrying current during normal operation and quenching arcs during interruption, eliminating the need for separate contact systems and reducing overall device complexity.
Solution Approach 2:
The contacts in the vacuum chamber are designed to serve multiple functions: they carry current during normal operation and simultaneously provide arc-quenching capability when the circuit is interrupted. This multi-functionality eliminates the need for separate specialized contact arrangements for each function.
3Object-affected harmful factors
If alternative insulation gases (dry air, oxygen, nitrogen, carbon dioxide) are used instead of SF6, then environmental impact is reduced, but arc-quenching capabilities deteriorate
Solution Approach 1:
The patent uses a vacuum chamber creating an inert vacuum environment that provides superior arc-quenching capabilities compared to atmospheric gases. The vacuum environment allows arcs to be extinguished more effectively while maintaining environmental friendliness, overcoming the limitations of alternative gases like air or nitrogen.
Solution Approach 2:
The patent changes the medium from gaseous alternatives (air, nitrogen, carbon dioxide) to a vacuum state, fundamentally altering the physical parameters of the insulating medium. This provides enhanced arc-quenching performance while maintaining environmental sustainability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The apparatus provides high-performance dielectric insulation and arc-quenching capabilities, enhances structural compactness and reliability, and can be manufactured at competitive costs, addressing the limitations of existing technologies.
Implementation Method 1
a vacuum interrupter, which comprises a fixed arc contact electrically connected to the fourth fixed contact, a movable arc contact electrically connected to the first fixed contact and reversibly movable along a corresponding translation axis between a coupled position with the fixed arc contact and an uncoupled position from the fixed arc contact. The vacuum interrupter additionally comprises a vacuum chamber, in which the fixed arc contact and the movable arc contact are enclosed and can couple or decouple.
Implementation Method 2
Some load-break switches have been developed, in which electric poles are immersed in pressurized dry air or other environment-friendly insulation gases, such as mixtures of oxygen, nitrogen, carbon dioxide and/or fluorinated gases.
Data Source
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AI summary
A switching apparatus comprising one or more electric poles. For each electric pole, the switching apparatus comprises a first pole terminal, a second pole terminal and a ground terminal. In operation, the first pole terminal can be electrically coupled to a first conductor of an electric line, the second pole terminal can be electrically coupled to a second conductor of said electric line and the ground terminal can be electrically coupled to a grounding conductor. For each electric pole, the switching apparatus comprises a plurality of fixed contacts spaced apart one from another. Such a plurality of fixed contacts comprises a first fixed contact electrically connected to the first pole terminal, a second fixed contact electrically connected to the second pole terminal, a third fixed contact electrically connected to the ground terminal and a fourth fixed contact electrically connectable with the second fixed contact. For each electric pole, the switching apparatus further comprises a movable contact, which is reversibly movable about a corresponding rotation axis according to opposite first and second rotation directions, so that said movable contact can be coupled to or uncoupled from one or more of the above-mentioned fixed contacts, and a vacuum interrupter comprising a vacuum chamber, in which a fixed arc contact and a movable arc contact are enclosed and can be coupled or decoupled. For each electric pole, the switching apparatus further comprises a motion transmission mechanism operatively coupled to the movable arc contact of said vacuum interrupter. The motion transmission mechanism is actuatable by the movable contact to cause a movement of said movable arc contact along said translation axis, when said movable contact moves about said rotation axis.